African 'Sanza' are thumb piano's some of which have a resonator in the form of a gourd, and occasionally in the Congo a human skull. Rods of steel or bamboo are lined up on the sound box and gently pushed down with the thumb.
William Bullock, an antiquarian, collector and traveller, commented in 1808 in the companion guide to his museum in Liverpool : 'when the slave piano is played by a skilful hand it produces an agreeable harmony'.
These two Sanza are both used to create music to accompany songs and are from the Democratic republic of the Congo, the Teke and Kongo peoples.